They shouldn’t forget to take their medication

lol serves its own grammatical function now I reckon.

It’s a marker for response to irony (actual irony, Americans…), or as a way to indicate you think something is stupid to the point of humour, or as a kind of “that tracks”.

Or at least, that’s how it’s used amongst people my age in Australia.

I don’t think I use it in a positive sense at all any more